A driver may be utilized to drive one or more switches to various conductive states. In one embodiment, a driver may be utilized to drive switches of a DC to DC converter. Such a DC to DC converter may convert an input DC voltage to an output DC voltage in response to driving signals from the driver. One type of DC to DC converter may have a pair of switches, e.g., a high-side switch and a low-side switch, arranged in a half bridge configuration responsive to drive signals from the driver to alternately turn ON and OFF in order to control the output DC voltage. In this situation, a short fault condition may occur if both the high and low side switch are ON simultaneously.
In order to avoid such a short fault condition, a driver may have break-before-make (BBM) control circuitry to ensure that one of the switches is OFF before the other switch is turned ON. The switches may be implemented as metal oxide semiconductor field effect transistors (MOSFETs). The BBM control circuitry may sense a voltage level between the gate and source terminals of the external MOSFET and compare it to a BBM threshold voltage level to determine a state of the MOSFET. If the gate to source voltage level is below the BBM threshold voltage level, it is determined the MOSFET is OFF.
However, a prior art driver embodiment may utilize the same bonding wire between a bonding pad of an integrated circuit and a package pin of the driver package for sensing the voltage level at the gate of the external MOSFET and for driving the MOSFET. Therefore, when a large driving current is delivered via this bonding wire an associated large voltage drop may occur. This may in turn degrade the reliability of the sensing function since the sensed voltage signal may be lowered due to the voltage drop caused by the large driving current.
For example, when such a driver is driving the external. MOSFET OFF a driving current signal provided along this single bonding wire may result in a large voltage drop. This large voltage drop may then interfere with the sensed signal such that the sensed signal is low enough to inadvertently indicate the external MOSFET is OFF when it actually is ON. This could then lead to the driver to drive both the high and low side switches ON at the same time creating a short fault condition between the high and low side switch. To avoid this situation, a prior art embodiment adds an extra time delay into the BBM sequence. However, this extra delay leads to a sub-optimal driving of the high and low side switches.
Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art. Accordingly, it is intended that the claimed subject matter be viewed broadly.